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Xinqian Zheng - One of the best experts on this subject based on the ideXlab platform.

  • stability improvement of a high pressure ratio Centrifugal compressor by flow injection
    Journal of Aerospace Engineering, 2020
    Co-Authors: Wenchao Zhang, Zhenzhong Sun, Baotong Wang, Xinqian Zheng
    Abstract:

    AbstractHigh-pressure ratio Centrifugal Compressors are required in modern turboshaft engines with the requirements of a high power-to-weight ratio and low fuel consumption. The reduction of the st...

  • effect of bent inlet pipe on the flow instability behavior of Centrifugal Compressors
    Chinese Journal of Aeronautics, 2020
    Co-Authors: Zhenzhong Sun, Tomoki Kawakubo, Hideaki Tamaki, Xinqian Zheng, Baotong Wang, Ryuusuke Numakura
    Abstract:

    Abstract Bent inlet pipes are often used in Centrifugal Compressors due to limited installation space, and an understanding of the effect on compressor stability is essential for safety and durability. This paper firstly investigates flow instability behaviors in two Compressors, one with a straight inlet pipe and the other with an S-shaped bent pipe. In detail, it analyzes the resulting flow fields, instability evolution paths and surge boundaries. The results show that the S-shaped pipe obviously affects the flow field at high mass flow rates, while reverse flow mainly influences the flow field at low mass flow rates. Reverse flow first occurs at certain flow passages with a high pressure difference that is predominantly decided by the volute rather than the S-shaped bent pipe. In addition, Centrifugal Compressors can tolerate reverse flow to some extent so that surge would not occur immediately if reverse flow occurs unless the reverse flow region extends circumferentially and radially to a sufficiently large size. Since the S-shaped pipe is not dominant in the creation and extension of reverse flow, it does not exacerbate the stability of the central compressor to a great extent. Last but not least, the S-shaped pipe is noted to delay the occurrence of surge at 90% rotating speed, which suggests the possibility of improving compressor stability with bent inlet pipes. This result differs from the conventional understanding that inlet distortion usually deteriorates compressor stability and emphasizes the particularity of Centrifugal Compressors.

  • influence of volute design on flow field distortion and flow stability of turbocharger Centrifugal Compressors
    Proceedings of the Institution of Mechanical Engineers Part D: Journal of Automobile Engineering, 2019
    Co-Authors: Zhenzhong Sun, Tomoki Kawakubo, Hideaki Tamaki, Xinqian Zheng, Zelin Linghu, Baotong Wang
    Abstract:

    Volute-induced distortion of the flow field remarkably exacerbates the flow stability of turbocharger Centrifugal Compressors; hence, reducing the flow field distortion by modifying the volute design is of great significance. This study investigated the influence of volute design on the flow field distortion and flow stability of turbocharger Centrifugal Compressors. Volutes with different throat areas and different area-to-radius ratio (Aθ/Rm) distributions were designed, and their performances were analyzed via both numerical and experimental methods. The results show that the throat area and the Aθ/Rm distribution significantly influence the volute-induced pressure distortion. By modifying the volute design, the amplitude of the pressure distortion can be reduced from 8.82% to 3.22%, and the stable flow range can be extended from 49.8% to 58.7%. Additionally, to reduce flow field distortion, the throat area should be appropriate to guarantee a match between the volute and upstream components, and the A...

  • roles and mechanisms of casing treatment on different scales of flow instability in high pressure ratio Centrifugal Compressors
    Aerospace Science and Technology, 2019
    Co-Authors: Xinqian Zheng
    Abstract:

    Abstract The development of single-stage high pressure ratio Centrifugal Compressors for small gas turbine engines is hindered by compressor flow instabilities with various temporal and spatial scales. In this paper, the effect of a self-recirculation casing treatment device for suppressing various scales of flow instability has been discussed. Rig tests of a high pressure ratio Centrifugal compressor with and without a casing treatment device are performed, and transient pressure signals are measured at endwalls by fast response pressure transducers. By analyzing measured pressure signals in both time and frequency domain, the casing treatment device is found effective in eliminating rotating instability and stall at the impeller inlet at low speeds, as well as suppressing surge of the compression system at middle and high speeds. The flow recirculation process generated inside the casing treatment device removes the vortical structures at the impeller inlet tip section, therefore eliminating the regional rotating instability and stall. Besides, the casing treatment device turns the pressure rise characteristics of the impeller more negative by enhancing the impeller work input, but turns that of the vaned diffuser more positive by increasing the incidence at the vaned diffuser inlet. Combining both effects, mild surge and the deep surge are suppressed.

  • experimental investigation of instability inducement and mechanism of Centrifugal Compressors with vaned diffuser
    Applied Thermal Engineering, 2018
    Co-Authors: Zhenzhong Sun, Xinqian Zheng, Tomoki Kawakubo
    Abstract:

    Abstract The paper is proposed to experimentally investigate the flow instability of Centrifugal Compressors with vaned diffuser, and the instability inducement and mechanism at full operating range are presented and analyzed in detail. In this paper, the steady performance and transient evolution process of the compressor are measured by steady and dynamic sensors. Experimental results show that the compressor experiences diverse flow instability patterns at different operating conditions. At low rotating speeds, the compressor undergoes stable state, stall and deep surge successively with mass flow rate decreases and the inducement of the flow instability is the wave-like instability disturbance at the impeller inlet. At middle rotating speeds, the compressor experiences stable state, mild surge and deep surge successively with mass flow rate reduces, and the inducement of the flow instability is the spike-shaped instability disturbance at the diffuser inlet. At high rotating speeds, the compressor still experiences stable state, mild surge and deep surge, whereas the flow instability is dominantly induced by the characteristic of the entire compression system. The research results of this paper promote understandings of the instability mechanism and improvements of the stability of Centrifugal Compressors.

Pericles Pilidis - One of the best experts on this subject based on the ideXlab platform.

  • A new method for reliable performance prediction of multi-stage industrial Centrifugal Compressors based on stage stacking technique: Part i - Existing models evaluation
    Applied Thermal Engineering, 2016
    Co-Authors: Waleed Al-busaidi, Pericles Pilidis
    Abstract:

    The growing acceptability of the natural gas as an energy source yields to place a higher research concentration on improving the Centrifugal compressor design and performance prediction techniques. This is the first part of a two-part study that aims to introduce a new integrated method for reliable performance prediction of multi-stage industrial Centrifugal compressor based on stage stacking technique. In this part, two most common existing models are adapted to be valid for industrial Centrifugal Compressors and the predicted characteristics are evaluated against measured data. Based on the conducted evaluation, a new model will be derived in the second part which incorporates the advantages of both approaches with more accurate prediction. Lüdtke method predicts the compressor design efficiency based on the correction of the derived experimental set of data. This approach has been applied for a single stage Centrifugal compressor at a single speed and flow values. Recently, Casey-Robinson method uses a new set of algebraic equations to obtain the compressor curve with less dependency on the geometrical features. This model has been tested with a single stage turbocharger compressor where the performance curve can be derived without considering the mechanical stages. This approximation will introduce a more significant impact when this method is used for large industrial Compressors. Therefore, these models will be improved to be suitable for multi-industrial Centrifugal Compressors and their prediction capability to estimate the performance map will be examined in this paper.

  • a new method for reliable performance prediction of multi stage industrial Centrifugal Compressors based on stage stacking technique part ii new integrated model verification
    Applied Thermal Engineering, 2015
    Co-Authors: Waleed Albusaidi, Pericles Pilidis
    Abstract:

    Abstract This is the second part of a conducted study to develop a new integrated model for reliable performance prediction of multi-stage industrial Centrifugal Compressors. The conducted evaluation in part 1 revealed a high deviation between the predicted surge flows using Casey–Robinson approach and measured values especially at low rotational speeds. Besides, a significant difference between the estimated and the experimental characteristics was observed at choke and surge conditions and this deviation is growing as the Mach number increases. One of the main disadvantages of this model is the dependency on the peak and design efficiencies and associated flow coefficients at both normal and low Mach number operations which are obviously not available at early preliminary stage. In contrast, Ludtke method fails to detect the instable flow regions and with lower degree of accuracy in the predicted efficiencies. However, the predicted design efficiency was found very close to the experimental value. Therefore, this paper introduces a new approach to estimate the performance map of multistage industrial Centrifugal Compressors based on stage staking principle and by incorporating the advantages of both methods. The new model has been tested at both low and high flow coefficients applications and for vaned and vaneless diffusers. Comparing with the existing models, the developed method was proven to generate more accurate estimation for performance characteristics of multistage Centrifugal Compressors with less dependency on the geometrical features. One of the unique advantages of the new method is the fact that it does not require a prior knowledge of the peak and design efficiencies and associated flow coefficients.

Nina F. Thornhill - One of the best experts on this subject based on the ideXlab platform.

  • supercritical fluid recycle for surge control of co2 Centrifugal Compressors
    Computers & Chemical Engineering, 2016
    Co-Authors: Sara Budinis, Nina F. Thornhill
    Abstract:

    This paper presents computer-based design and analysis of control systems for Centrifugal Compressors when the operating fluid is supercritical CO2. It reports a non-linear dynamic model including a main forward compression line and two different configurations for the recycle antisurge line. Disturbance scenarios are proposed for testing the configurations and performance indicators are suggested to evaluate control performance and power consumption of the compression system. The paper demonstrates that compared to the hot recycle, the process configuration including a cold gas recycle has better overall stability, but higher power consumption and lower values for the control performance indicators. Based on the previous considerations, the paper gives suggestions regarding the choice of the recycle configuration. Moreover it compares subcritical and supercritical compression during surge prevention and highlights the importance of the selection of the gas recycle configuration when full recycle is needed.

  • Supercritical gas recycle analysis for surge control of Centrifugal Compressors
    12th International Symposium on Process Systems Engineering and 25th European Symposium on Computer Aided Process Engineering, 2015
    Co-Authors: Sara Budinis, Nina F. Thornhill
    Abstract:

    Abstract This paper presents computer-based analysis and design of control systems for Centrifugal Compressors when the operating fluid is supercritical CO2. It demonstrates that the design of the control system of the compressor must take into account the state of the fluid. It also evaluates if the plant configuration allows compressor operation within a given surge margin. The results show the impact of the operating conditions of the compression station on surge prevention, their effect on the energy consumption, and suggest ways of dealing with supercritical fluid while controlling a compressor.

  • control of Centrifugal Compressors via model predictive control for enhanced oil recovery applications
    IFAC-PapersOnLine, 2015
    Co-Authors: Sara Budinis, Nina F. Thornhill
    Abstract:

    Abstract This paper proposes a control system for integrated pressure and surge control of Centrifugal Compressors for enhanced oil recovery application. The proposed control system is based on linear model predictive control. A fully validated non-linear dynamic model was developed in order to simulate the operation of the compressor at full and partial load. The model of the compression system includes a main process line with the compressor and a recycle line with the antisurge recycle valve. Different disturbance and control tuning scenarios were tested and the response of the model predictive controller was analysed, evaluated and also compared with a traditional control system. Temperature effects have been taken into account in the model of the process and in the constraint formulation of the MPC optimization problem. The results show that the proposed control technique is able to meet the process demand while preventing surge and also minimizing the amount of gas recycle.

  • Systematic One Zone Meanline Modelling of Centrifugal Compressors for Industrial Online Applications
    Volume 6C: Turbomachinery, 2013
    Co-Authors: Matteo Cicciotti, Nina F. Thornhill, Ricardo Martinez-botas, Alessandro Romagnoli, Stephanie Geist, Axel Schild
    Abstract:

    For developing model-based online applications such as condition monitoring and condition-based maintenance or real-time optimization, highly representative and yet simple physical models of Centrifugal Compressors are necessary. Previous investigations have shown that in this context meanline models represent a valid alternative to the commonly used empirical based modelling methodologies such as polynomial regression models or artificial neural networks.This paper provides a methodology for tailoring meanline models to multistage Centrifugal Compressors by appropriate selection and adaptation of loss correlations. Guidelines for the selection of the boundary conditions are also provided.The potential of the methodology is demonstrated in the Proof-of-concept section using two sets of data obtained from an air multistage Centrifugal compressor operated in BASF SE, Ludwigshafen, Germany. The first set of data was used to calibrate the model whereas the second one was used for validation. The model results show that the predictions of stagnation temperature and pressure at the outlet of the stage deviate from the measurements respectively 0.15–3% and of 0.66–1.1% respectively. The results are discussed in the current paper.Copyright © 2013 by ASME

Sara Budinis - One of the best experts on this subject based on the ideXlab platform.

  • supercritical fluid recycle for surge control of co2 Centrifugal Compressors
    Computers & Chemical Engineering, 2016
    Co-Authors: Sara Budinis, Nina F. Thornhill
    Abstract:

    This paper presents computer-based design and analysis of control systems for Centrifugal Compressors when the operating fluid is supercritical CO2. It reports a non-linear dynamic model including a main forward compression line and two different configurations for the recycle antisurge line. Disturbance scenarios are proposed for testing the configurations and performance indicators are suggested to evaluate control performance and power consumption of the compression system. The paper demonstrates that compared to the hot recycle, the process configuration including a cold gas recycle has better overall stability, but higher power consumption and lower values for the control performance indicators. Based on the previous considerations, the paper gives suggestions regarding the choice of the recycle configuration. Moreover it compares subcritical and supercritical compression during surge prevention and highlights the importance of the selection of the gas recycle configuration when full recycle is needed.

  • Supercritical gas recycle analysis for surge control of Centrifugal Compressors
    12th International Symposium on Process Systems Engineering and 25th European Symposium on Computer Aided Process Engineering, 2015
    Co-Authors: Sara Budinis, Nina F. Thornhill
    Abstract:

    Abstract This paper presents computer-based analysis and design of control systems for Centrifugal Compressors when the operating fluid is supercritical CO2. It demonstrates that the design of the control system of the compressor must take into account the state of the fluid. It also evaluates if the plant configuration allows compressor operation within a given surge margin. The results show the impact of the operating conditions of the compression station on surge prevention, their effect on the energy consumption, and suggest ways of dealing with supercritical fluid while controlling a compressor.

  • control of Centrifugal Compressors via model predictive control for enhanced oil recovery applications
    IFAC-PapersOnLine, 2015
    Co-Authors: Sara Budinis, Nina F. Thornhill
    Abstract:

    Abstract This paper proposes a control system for integrated pressure and surge control of Centrifugal Compressors for enhanced oil recovery application. The proposed control system is based on linear model predictive control. A fully validated non-linear dynamic model was developed in order to simulate the operation of the compressor at full and partial load. The model of the compression system includes a main process line with the compressor and a recycle line with the antisurge recycle valve. Different disturbance and control tuning scenarios were tested and the response of the model predictive controller was analysed, evaluated and also compared with a traditional control system. Temperature effects have been taken into account in the model of the process and in the constraint formulation of the MPC optimization problem. The results show that the proposed control technique is able to meet the process demand while preventing surge and also minimizing the amount of gas recycle.

Zhenzhong Sun - One of the best experts on this subject based on the ideXlab platform.

  • stability improvement of a high pressure ratio Centrifugal compressor by flow injection
    Journal of Aerospace Engineering, 2020
    Co-Authors: Wenchao Zhang, Zhenzhong Sun, Baotong Wang, Xinqian Zheng
    Abstract:

    AbstractHigh-pressure ratio Centrifugal Compressors are required in modern turboshaft engines with the requirements of a high power-to-weight ratio and low fuel consumption. The reduction of the st...

  • effect of bent inlet pipe on the flow instability behavior of Centrifugal Compressors
    Chinese Journal of Aeronautics, 2020
    Co-Authors: Zhenzhong Sun, Tomoki Kawakubo, Hideaki Tamaki, Xinqian Zheng, Baotong Wang, Ryuusuke Numakura
    Abstract:

    Abstract Bent inlet pipes are often used in Centrifugal Compressors due to limited installation space, and an understanding of the effect on compressor stability is essential for safety and durability. This paper firstly investigates flow instability behaviors in two Compressors, one with a straight inlet pipe and the other with an S-shaped bent pipe. In detail, it analyzes the resulting flow fields, instability evolution paths and surge boundaries. The results show that the S-shaped pipe obviously affects the flow field at high mass flow rates, while reverse flow mainly influences the flow field at low mass flow rates. Reverse flow first occurs at certain flow passages with a high pressure difference that is predominantly decided by the volute rather than the S-shaped bent pipe. In addition, Centrifugal Compressors can tolerate reverse flow to some extent so that surge would not occur immediately if reverse flow occurs unless the reverse flow region extends circumferentially and radially to a sufficiently large size. Since the S-shaped pipe is not dominant in the creation and extension of reverse flow, it does not exacerbate the stability of the central compressor to a great extent. Last but not least, the S-shaped pipe is noted to delay the occurrence of surge at 90% rotating speed, which suggests the possibility of improving compressor stability with bent inlet pipes. This result differs from the conventional understanding that inlet distortion usually deteriorates compressor stability and emphasizes the particularity of Centrifugal Compressors.

  • influence of volute design on flow field distortion and flow stability of turbocharger Centrifugal Compressors
    Proceedings of the Institution of Mechanical Engineers Part D: Journal of Automobile Engineering, 2019
    Co-Authors: Zhenzhong Sun, Tomoki Kawakubo, Hideaki Tamaki, Xinqian Zheng, Zelin Linghu, Baotong Wang
    Abstract:

    Volute-induced distortion of the flow field remarkably exacerbates the flow stability of turbocharger Centrifugal Compressors; hence, reducing the flow field distortion by modifying the volute design is of great significance. This study investigated the influence of volute design on the flow field distortion and flow stability of turbocharger Centrifugal Compressors. Volutes with different throat areas and different area-to-radius ratio (Aθ/Rm) distributions were designed, and their performances were analyzed via both numerical and experimental methods. The results show that the throat area and the Aθ/Rm distribution significantly influence the volute-induced pressure distortion. By modifying the volute design, the amplitude of the pressure distortion can be reduced from 8.82% to 3.22%, and the stable flow range can be extended from 49.8% to 58.7%. Additionally, to reduce flow field distortion, the throat area should be appropriate to guarantee a match between the volute and upstream components, and the A...

  • experimental investigation of instability inducement and mechanism of Centrifugal Compressors with vaned diffuser
    Applied Thermal Engineering, 2018
    Co-Authors: Zhenzhong Sun, Xinqian Zheng, Tomoki Kawakubo
    Abstract:

    Abstract The paper is proposed to experimentally investigate the flow instability of Centrifugal Compressors with vaned diffuser, and the instability inducement and mechanism at full operating range are presented and analyzed in detail. In this paper, the steady performance and transient evolution process of the compressor are measured by steady and dynamic sensors. Experimental results show that the compressor experiences diverse flow instability patterns at different operating conditions. At low rotating speeds, the compressor undergoes stable state, stall and deep surge successively with mass flow rate decreases and the inducement of the flow instability is the wave-like instability disturbance at the impeller inlet. At middle rotating speeds, the compressor experiences stable state, mild surge and deep surge successively with mass flow rate reduces, and the inducement of the flow instability is the spike-shaped instability disturbance at the diffuser inlet. At high rotating speeds, the compressor still experiences stable state, mild surge and deep surge, whereas the flow instability is dominantly induced by the characteristic of the entire compression system. The research results of this paper promote understandings of the instability mechanism and improvements of the stability of Centrifugal Compressors.